t Scores and Procedures

Similar to a z score, t scores measure the relative location of a score within a distribution. The distribution
of t scores is a standardized distribution which has a mean of 50 and standard deviation
of 10.

The resources in this section focus exclusively on the t statistic and the statistical procedures for which it can be used.

t Scores & Procedures

SPSS Software Tutorials

Other Software

t Scores & Procedures

t Statistics: An Introduction

t Statistics: An Introduction

t Procedures: Inferences about the Population Mean

t Procedures are very similar to the z procedures and are used when the distribution
of the data are not perfectly normal, and when the population standard deviation of
a variable is unknown. The interpretation of t scores is similar to the interpretation
of z scores. However, the t distribution has a slightly different shape. It is symmetric,
but not normal. It has a single peak, and a mean of 0, which is the center of the
distribution, but that tails are higher and fatter, and the distribution has more
spread. Further, the t distribution looks different for different sample sizes. The
following presentation describes the properties of the t distribution, and demonstrates
how to use t scores to make inferences about a population mean and to compare matched
samples. The software tutorials show how to conduct these procedures in SPSS.

t Procedures: Comparing Independent Samples

t procedures can be used to compare variables across two independent samples. For
instance, researchers may want to know whether the average performance on a certain
achievement test differs significantly between males and females. The following narrated
presentation demonstrates how to estimate a confidence interval for the mean difference
between two populations, and how to test whether this difference is statistically
significant. The presentation also discusses of the assumptions that must be met,
and the robustness of t procedures to the violation of these assumptions. The software
tutorial demonstrates how to perform an independent samples t test using SPSS.